It is already known that seat mats for a vehicle seat are measured, in terms of their function and in order to record readings, either with a plunger having a defined weight or in an overpressure chamber. The plunger has a specific weight, for example 400 g, while in the case of the overpressure chamber, a variety of readings can be generated by modifying the overpressure in a pressure chamber. The pressure chamber is approximately the same size as the scat mat, and is suitable for resisting a defined overpressure.